CHAPTER 1

The World Without Teeth: Demographic Trends

Philippe Mojon

Edentulism, defined as having no teeth, is usually the result of dental caries and periodontal disease. In the case of the latter, the natural course of the disease leads to the loss of all teeth only in a very small percentage of people. The same pattern is probably true with caries, although observational studies are rare. Edentulism cannot be seen, therefore, as the ultimate stage of pathologic processes, but the result of extraction of teeth more or less compromised by diseases. The removal of teeth is related to a series of factors of which the extent of the caries attack or periodontal breakdown may play only a minor role. On many occasions, it is a measure used to prevent future pain, to lower the cost associated with dental treatment, or to avoid anxiety related to dental visits.¹ The number of teeth extracted at the time of full clearance has dropped significantly over the last 20 years in industrialized countries, and today most cases involve the removal of about six teeth.^2,3 Dentists and patients usually agree when full clearance is the most reasonable choice of treatment; however, in 15% of cases, the demand comes from the patient while the dentist would have preferred to keep at least some of the teeth.² Among the most frequently cited factors that influence edentulism in a given area are economic wealth, education, the availability and use of professional and preventive services, oral health care systems, third-party payment, dental awareness, and social beliefs. The end result is that edentulism varies widely between countries and also between regions. It also means that edentulism varies over time since the factors themselves evolve over the years.

The gold standard of edentulism evaluation in a given area is to conduct a clinical survey and to identify edentulous people. The survey is the method of choice in less developed countries. The number of people surveyed has to be large enough to be representative and the selection of subjects has to be randomized. An acceptable substitute for clinical observation is simply to ask the question “How many teeth do you have?” The question may be administered in a written questionnaire or by telephone interview; both methods have good validity.^4,5 Hence, it seems relatively simple to measure edentulism in countries by conducting surveys and taking a census on a regular basis. Yet, a review of the data available for the rate of edentulism for the period from 1985 to 2000 revealed that only 37 of the 190 countries in the United Nations had carried out a randomized survey. The information was taken from peer-reviewed papers (II countries), publicly accessible databases or reports (Canada, United Kingdom, and United States), and the World Health Organization (WHO) website on oral health (23 countries). Information was deemed relevant when the sample was representative of the country and age class (spanning a maximum of 10 years). Only eight countries (Canada, China, Finland, Iceland, Norway, Sweden, United Kingdom, and United States) have detailed data for various age classes and regions.